Airplane propeller



pt. 3. 1940- w. H. KELLY 2,213,497

AIRPLANE PROPELLER Original Filed June 21, 1938 2 Sheets-Sheet 1INVENTOR.

l V/LL/AM b. flaz ATTORNEY.

Sept. 3, 1940. w. H. KELLY AIRPLANE PROPELLER Original Filed June 21,1938 2 Sheets-Sheet 2 INVENTOR. LIAM H /fLL y.

Patented Sept. 3, 1940 UNITED STATES AIRPLANE PROPELLER William H.Kelly, Denver, 0010.

Application June 21,

1938, Serial No. 214,887

Renewed December 22, 1939 Claims.

pulsion and prevent the air from being thrown centrifugally outward.

The basic idea is to design a propeller which will havecircumferentially extending channels with side walls sufficiently deepto prevent the air from escaping radially or centrifugally from theblades so that all of the air will be projected rearwardly in a solid,powerful, propelling stream.

Other objects and advantages reside in the detail construction of theinvention, which is designed for simplicity, economy, and efficiency.These will become more apparent from the following description.

In the following detailed description of the invention reference is hadto the accompanying drawings which form a part hereof. Like numeralsrefer to like parts in all views of the drawings and throughout thedescription.

In the drawings:

Fig. 1 illustrates one embodiment of the invention.

Fig. 2 is a section therethrough taken on the line 2-2, Fig. 1.

Fig. 3 is a similar section illustrating the sam construction with agreater pitch.

Fig. 4 is a similar section illustrating a still greater pitch.

Fig. 5 is an alternate form of the construc- 40 tion of Fig. 1, in whichthe propelling cups are circumferentially curved.

Fig. 6 is a plan view of the form of Fig. 5.

Figs. '7, 8, and 9 illustrate various adaptations of the principle ofthe invention.

Fig. 10 is a face view of a propeller in which the preferred form of theinvention is embodied.

Fig. 11 is a rear View of the propeller, of Fig. 10.

50 Figs. 12, 13, 14, 15, and 16 are blade sections of the form of Fig.10, taken on the lines corresponding to their respective figure numbers.

The highly-efficient effects of this propeller are obtained from the useof curved air-cups 55 mounted torotate about an axis and opening in thedirection of rotary travel and at their rearward faces. In Fig. 1, twosuch cups are illustrated at I 1 mounted on the extremities of radialarms I8 projecting from a hub I9. The cups I! are scoop-shaped andcompletely curve-linear, as shown in Fig. 2 so that a line drawn ontheir surfaces at any point will be a curved line. The arms I8 passcompletely through the cups to form a substantial, balanced supporttherefor. This relieves the cups of structural stress and allows them tobe formed of relatively thin, light, material. All of the stresses areabsorbed by the arms I8.

A streamlined shell or vane 20 surrounds the arm l8 where it crosses thecup to prevent the arm from creating air resistance within the cup. Thestreamlined shell 20 is loosely mounted on the arm so that it 'mayrotate to a position in the plane of least resistance in the air streamand, because of its shape, it presents very little if any resistance tothe flow of the air. When the propeller is not rotating, the vanes 20hang vertically downward but when the propeller is rotated, the vanes 20immediately assume their most eflicient position. v

The curvature of the cups l'l may be designed to produce any desiredpitch, as shown in Figs. 2, 3, and 4 by the broken arrows.

Fig. 5 illustrates the same principle in another form. In this form,however, the inner faces of the cups are flattened, as shown at 2|, and

curved upon a circumference around the hub so as to reduce anyturbulence caused by the trailing edges thereof.

Figs. '7, 8, and 9 show quarter-spherical cups mounted in variouspositions relative to the hub. The cups of Figs. 7 and 8 are inclined tooffset the centrifugal or outward effect of the air and are designed tothrow it in a compact rearward air stream. Fig. 9 illustrates the sameprinciple with the cups mounted at the hub without supporting arms.

In Fig. 10, the cups or pockets are embodied in a radially extendingpropeller blade. The blades each consist of a curved outer shell 22which is divided throughout its length by means of lateral partitionplates 23; closed at its outer extremity by means of an end plate 24;and at its inner extremity by an inner end plate 25. The blades aresupported upon tapered, tubular arms 26 which extend radially outwardfrom a hubmember 21 throughout the entire length of the blade. The armsextend through, and are secured to, eachof the partition plates 23. Theplates 23 separate the blade length into curved pockets having crosssections of the forms indicated in Figs. 12 to 16.

In each pocket, a stream-lined shell or vane 28 is mounted on the arm 26and is free to rotate thereon so as to automatically resume the mosteffective position for streamlining the arms 26.

While specific forms of the improvement have been described andillustrated herein, it is desired to be understood that the same may bevaried, within the scope of the appended claims, without departing fromthe spirit of the invention.

Having thus described the invention, what is claimed and desired securedby Letters Patent 1. A propeller constriction comprising: a hub; armsextending radially outward from said hub; scoop-shaped cups mounted onsaid arms, said cups being open in the direction of rotation and attheir rearward faces so as to receive a stream of air, curve it, andexpel it rearwardly, said arms extending across said cups to support thelatter; and stream-lined vanes formed on said arms within said cups.

2. A blade construction for propellers comprising: a hub member; a bladearm extending radially outward from said hub member; a curved propellershell positioned to receive a stream of air from the direction ofrotation and discharge it rearwardly; and a series of lateral,intermediate partition plates within said shell, said arm passingthrough all of said plates to act as a support for said shell.

3. A blade construction for propellers comprising: a hub member; a bladearm extending radially outward from said hub member; a curved propellershell positioned to receive a stream of air from the direction ofrotation and discharge it rearwardly; a series of lateral, intermediatepartition plates within said shell,

said arm passing through all of said plates to act as a support for saidshell; and stream-lined shield members hanging loosely on said armsbetween each pair of said partition plates, said shell being inclinedwith reference to said blade arm so asto gradually approach the latteras the distance from the axis is increased.

4. A blade construction for propellers comprising: a hub member; armsextending radially outward from said hub member; transversely curvedpropeller shells mounted on said arms, said shells having the largestcross-sectional area near the said hub member and tapering graduallytoward the outer end where the crosssection area is comparatively small.

5. A blade construction for propellers comprising: a hub member;scoop-shaped cups mounted radially outward on said hub member, said cupsbeing open in the direction of rotation and at their rearward faces soas to receive a stream of air, curve it, and expel it rearwardly, saidcups being completely curvated so that any line on their inner or outersurfaces will be a curved line.

' WILLIAM H. KELLY.

